Substrate for reducing electromagnetic interference and enclosure

Abstract

A substrate for reducing electromagnetic emissions is provided. The substrate may include a plurality of ground layers, signal layers and power layers. All of the layers other than the ground layer are provided with a ground ring that may extend around the perimeter of the layer. The ground rings are electrically coupled together by ground stitching or vias that are randomly spaced. The random spacing of the ground stitching is based on the operating frequencies of the integrated circuit devices mounted on the substrate. Additional shielding may be provided by providing a cover assembly made of any conductive material that is coupled to the exposed ground rings on the uppermost and lowermost surfaces of the substrate. The cover assembly is coupled to the exposed ground rings in a randomized pattern. The device provides a virtual electrical ground cage in which the internal signal layers are totally enclosed, thereby reducing electromagnetic emissions.

Description

1. Field of the InventionThis invention relates generally to a substrate upon which integrated circuit components are mounted and, more particularly, to a substrate that reduces electromagnetic emissions and associated electromagnetic interference problems.2. Description of the Related ArtIn the field of electronics, various integrated circuit components, such as microprocessors, are commonly mounted on a substrate. This substrate is typically comprised of ground layers, signal layers, and power layers. The signal layer contains traces that allow the transmission of various signals between the various integrated circuit components positioned on the substrate.It is well known in the art that signals traveling within these traces can produce electromagnetic emissions, i.e., radiated electrical fields. Electromagnetic interference ("EMI") can cause several problems, such as malfunctions of nearby electrical devices and interference or degradation of signals traveling along other traces...

AI Technical Summary

Problems solved by technology

Electromagnetic interference ("EMI") can cause several problems, such as malfunctions of nearby electrical devices and interference or degradation of signals traveling along other traces.

EMI problems have resulted in the Federal Communications Commission adopting guidelines for maximum allowable levels of electromagnetic emissions in various electronic devices.

It is also well known that faster signal speeds lead to more EMI problems.

With the emphasis on increased operating speeds of today's integrated circuit devices, EMI problems also increase.

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